Posts Tagged ‘cable’

Units of Measurement – Broadband Internet Access Speed

bit= smallest unit of digital information, i.e. ones & zeros
byte= a set of bits
bps= bits per second
Kbps= kilobits per second =1000 bits per second
Mbps = Million bits per second =1,000,000 bits per second
Gbps = Gigabits per second = 1,000,000,000 (one billion) bits per second
Tbps = Terabits per second = 1,000,000,000,000 (one trillion) bits per second

T1

T2

Cable/DSL

Verizon FIOS

T3

Download Speed Can Reach (kb/s)

1,544

6,312

8,000

30,000

44,736

Download Speed Can Reach (kB/s)

193

789

1,000

5,592

3,750

It seems people still have a notion that “dedicated T’s are the pinnacle of data telecom service. Why buy a dedicated T1, T3, etc. when alternative technologies are reaching/surpassing their performance for a fraction of the cost?

Note 1: Cable/DSL speeds are listed at somewhat of a maximum of what people are seeing today.

Note 2: Upload speeds for businesses that are hosting technology can be an important consideration, and Cable/DSL providers typically limit the uploads speeds significantly.� Verizon’s FIOS, on the other�hand, starts with 2,000 kb/s and goes up to 5,000 kb/s for upload — still quite a bit faster than a T1.

If you want 99.99% or more guaranteed uptime through a SLA (Service Level Agreement) and a guaranteed 1544kb/s Up and 1544kb/s Down 24/7, then a T1,T2, or T3 connection are what you need. If you are ok with a few hours of outages, no decent SLA (ask Verizon for an SLA), a shared connection where if your neighbors use all the bandwidth (or through DDoS) then you start to have slow connections, Disabled ports, or to shutoff your service if spam or other issue detected.. without trying hard to contact you.

For Home/Personal.. or a business that does not ’serve/host other businesses’ and just uses email and web.. then I suggest FIOS!

Also, an idea, I do suggest a 24/7 business have 2 connections to every server they have. 1 will be the tried and true T1 line (or T2) and the other will be the unreliable (at least not 99.999%), but extremely fast, FIOS. When FIOS has its outages, then your server will still be able to communicate through the trusty T1 line. However, this will only work with Name-Based failover/redundancy and not IP addresses (useful for websites, ftp sites, and even Oracle database connections by hostname and not IP address).

Internet Connection Speed Comparison Chart

This chart is provided by Summersault to help you understand the different kinds of internet connection technologies available. (If you’re in Richmond/Wayne County Indiana, see a list of available local connection options.)

Carrier Technology

Description

Speed

Physical Medium

Comments

Dial-up Access

On demand access using a modem and regular telephone line (POT).

2400 bps to 56 Kbps

Twisted pair (regular phone lines)

Cheap but slow compared with other technologies.

Speed may degrade due to the amount of line noise

ISDN

Dedicated telephone line and router required.

64 Kbps to 128 Kbps

Twisted pair

Not available everywhere but becoming more widespread.

An ISDN line costs slightly more than a regular telephone line, but you get 2 phone lines from it.

56K ISDN is much faster than a 56K dialup line

Cable

Special cable modem and cable line required.

512 Kbps to 20 Mbps

Coaxial cable; in some cases telephone lines used for upstream requests.

Must have existing cable access in area.

Cost of bring service into an area and trenching cable can be prohibitive.

Networkable

ADSL/DSL

Asymmetric Digital Subscriber Line

(ADSL is the same as DSL)

This new technology uses the unused digital portion of a regular copper telephone line to transmit and receive information. ADSL is asymmetric since it recieves at 6 to 8 Mbps per second but can only send data at 64 Kbps.

A special modem and adapter card are required.

128 Kbps to 8 Mbps

Twisted pair (used as a digital, broadband medium)

Doesn’t interfere with normal telephone use.

Bandwidth is dedicated, not shared as with cable.

Bandwidth is affected by the distance from the network hubs. Must be within 5 km (3.1 miles) of telephone company switch.

Limited availability.

Not networkable

Wireless (LMCS)

Access is gained by connection to a high speed cellular like local multi-point communications system (LMCS) network via wireless transmitter/receiver.

30 Mbps or more

Airwaves

Requires outside antenna.

Can be used for high speed data, broadcast TV and wireless telephone service.

In older versions, the computer sends request for information to an ISP via normal phone dial-up communications and data is returned via high speed satellite to rooftop dish, which relays it to the computer via a decoder box.

6 Mbps or more

Airwaves

Requires outside antenna.

Bandwidth is not shared.

Satellite companies are set to join the fray soon which could lead to integrated TV and Internet service using the same equipment and WebTV like integrated services

Latency is typically high

Some connections require an existing Internet service account.

Setup fees can range from $500-$1000.

Frame Relay

Provides a type of “party line” connection to the Internet.

Requires a FRAD (Frame Relay Access Device) similar to a modem, or a DSU/CSU.

56 Kbps to 1.544 Mbps (or more, depending on connection type)

Various

May cost less than ISDN in some locations.

Limited availability.

Uses one of the connection types below, fractional up to OC3

Fractional T1

(Flexible DS1)

Only a portion of the 23 channels available in a T1 line is actually used.

64 Kbps to 1.544 Mbps

Twisted-pair or coaxial cable

Cheaper than a full T1 line with growth options of 56 Kbps or 64 Kbps increments as required.

T1

Special lines and equipment (DSU/CSU and router) required.

1.544 Mbps

Twisted-pair, coaxial cable, or optical fiber

Typically used for high bandwidth demands such as videoconferencing and heavy graphic file transfers.

Minimum for large businesses and ISPs.

Expensive

T3

Typically used for ISP to Internet infrastructure.

44.736 Mbps

Optical fiber

OC-1

Typically used for ISP to Internet infrastructure within Internet infrastructure.

51.84 Mbps

Optical fiber

OC-3

Typically used for large company backbone or Internet backbone.

155.52 Mbps

Optical fiber

About Bandwidth

Bandwidth, or capacity, refers to the amount of data a given technology or infrastructure can transmit over time. It is usually expressed in kilobits per second (Kbps) or megabits per second (Mbps).

There is often confusion about bandwidth due to the difference between kilobytes and kilobits. Bits are used to talk about data transfer rates (1 kilobit = 1000 bits), while bytes are used to talk about storage size calculations (1 kilobyte = 1024 bytes). There are 8 bits in a byte. So a 28.8 Kbps (kilobits per second) modem can actually only handle a maximum of 3.6 KB/s (kilobytes per second) of data, including the connection to the ISP, the data holding the TCP/IP packets together, and other essential information. Given all these facts together, your download speeds will often be slower than the “potential” advertised.

About Latency

Latency, or “network latency” refers to the speed at which traffic is traveling over an internet connection. It is usually measured according the round-trip time that it takes a single chunk of data to reach a remote host and then come back. This is not always the best measure of overall performance, however, as it is possible for a high latency link to also be a high bandwidth link (Satellite and DSL are good examples of this.)

Parts of this document were originally obtained from from Ontario Library Services in Canada. Updated in 09-2000 with help from Alan Moore and various other web resources. Last significant update on 10-11-2005.

The abbreviation for bit is a lowercase “b”; the abbreviation for byte is an uppercase “B”. Their are 8 bits in a Byte.

Modem

Dial up modem speed is measured in Kilo and Mega bits. Dial up modem speeds are pretty much tapped out at their high end of 56Kb due to the noise that exists on standard POTS copper telephone lines. A few companies have toyed with filtering systems to help quiet the lines but with the newer packet lines taking over the market place we may someday see these POTS lines disappear altogether.

DSL

Digital Subscriber Line (DSL) is a broadband internet service that is delivered right through your regular phone line and is often supplied by your local telephone company. Although it uses your phone lines, it does not interfere in anyway with you telephone, caller id, answering machine or other telephone equipment. It is typically available in speeds from 144Kb to 3Mb, but even faster speeds are available from some providers.

aDSL

A type of DSL common for residential use is Asymmetric Digital Subscriber Line (ADSL). It is asymmetrical in the sense that it can download (receive) data much faster than it can upload (send) data. Typical internet surfing mainly involves downloading data from web servers, so this asymmetry works out fine for home use. Plus this asymmetry often allows for large cost savings.

sDSL

A type of DSL that is common for business use is Symmetric Digital Subscriber Line (SDSL). With SDSL you get the same bandwidth (speed) in each direction. Although it is typically much more expensive than ADSL, it is better if you are running a web server or conducting other activities which would require a lot of data to be sent.

Cable

Cable internet access is generally offered by the same companies that provide cable TV. It works on the same coaxial cable that the TV signal comes in on, but doesn’t effect your TV signal. Therefore you can use the internet and watch TV at the same time. Typically, cable internet access provide a maximum of 1.5 – 6MB of bandwidth on the system. However, everyone on your network segment is sharing that bandwidth, so performance can be much lower, especially if a lot of people in your neighborhood use the service. Some cable providers may limit your individual bandwidth, so that you will never see the peak bandwidth even when your network segment is clear.

Satellite

With satellite internet access, data is sent between a small satellite dish at your home and the satellite in space. This data is then relayed to a base station that has a direct connection to the internet and acts as a hub. Especially for those in rural areas that cannot get DSL or Cable internet access, a satellite ISP can be a good way to get broadband service. Some satellite systems use a phone line and others use a in-sight tower system to send upstream requests.